title: Mia40 and MINOS act in parallel with Ccs1 in the biogenesis of mitochondrial Sod1.
abstract: Superoxide dismutase 1 (Sod1) is a major superoxide-scavenging enzyme in the eukaryotic cell, and is localized in the cytosol and intermembrane space of mitochondria. Sod1 requires its specific chaperone Ccs1 and disulfide bond formation in order to be retained in the intermembrane space. Our study identified a pool of Sod1 that is present in the reduced state in mitochondria that lack Ccs1. We created yeast mutants with mutations in highly conserved amino acid residues corresponding to human mutations that cause amyotrophic lateral sclerosis, and found that some of the mutant proteins were present in the reduced state. These mutant variants of Sod1 were efficiently localized in mitochondria. Localization of the reduced, Ccs1-independent forms of Sod1 relied on Mia40, an essential component of the mitochondrial intermembrane space import and assembly pathway that is responsible for the biogenesis of intermembrane space proteins. Furthermore, the mitochondrial inner membrane organizing system (MINOS), which is responsible for mitochondrial membrane architecture, differentially modulated the presence of reduced Sod1 in mitochondria. Thus, we identified novel mitochondrial players that are possibly involved in pathological conditions caused by changes in the biogenesis of Sod1.
authors.affiliation: International Institute of Molecular and Cell Biology, Warsaw, Poland.
authors.forename: Aksana
authors.initials: A
authors.lastname: Varabyova
authors.forename: Ulrike
authors.initials: U
authors.lastname: Topf
authors.forename: Paulina
authors.initials: P
authors.lastname: Kwiatkowska
authors.forename: Lidia
authors.initials: L
authors.lastname: Wrobel
authors.forename: Magdalena
authors.initials: M
authors.lastname: Kaus-Drobek
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Chacinska
mesh_terms: D000595:Amino Acid Sequence; D004220:Disulfides / Q000378:metabolism; D006801:Humans; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000072105:Superoxide Dismutase-1
chemical_list: C491960:CCS1 protein, S cerevisiae; D004220:Disulfides; C495320:MIA40 protein, S cerevisiae; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; C000606290:SOD1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1
keywords: ALS; MINOS/MICOS/MitOS; Mia40; mitochondrial intermembrane space; protein biogenesis and transport